For example, carrying equipment that carries items generally employs a configuration that supports a carried item to be transportable, using a free ball bearing with one omnidirectionally rotatable protruding ball (main ball).
In the carrying equipment, a stopper that hits against the item, a cushion, a guide member that is in contact with the item, and the like may be provided separately from the free ball bearing to stop or decelerate movement of the item that is being carried. Recently, a configuration in which the free ball bearing itself can apply a braking force to the item that is being carried has been proposed (for example, Patent Document 1). Conveying equipment using the free ball bearing is advantageous in that it not necessary to dispose a stopper, a cushion, or a guide member.
The free ball bearing (a device for supporting a transportation ball body) shown in FIGS. 1A and 1B in Patent Document 1 includes a recessed round member that supports a main ball to be rotatable on a recessed round surface through a plurality of sub-balls and a cover member that has an inner hole through which the upper portion of the main ball protrudes, in which a rotatable state where the main ball is close to the rim of the inner hole with a small gap between the rim of the main ball and the inner hole and a braking state where the rim of the inner hole is in press-contact with the main ball are switched.
Further, in FIGS. 2A and 2B of Patent Document 1, show a free ball bearing (device for supporting a ball body) having a configuration that, when a pressing member having a ring-shaped sub-ball contact portion moves down due to being moved up and down by a driving means (in detail, an electromagnet 34 with a magnet coil), applies a braking operation to the rotation of a main ball by bringing the sub-ball contact portion of the sub-balls in contact with the upper edge of a group of the sub-balls to restrict the movement of the sub-balls.